U.S. patent number 11,384,758 [Application Number 16/635,810] was granted by the patent office on 2022-07-12 for cylindrical symmetric volumetric machine with an inlet ventilator.
This patent grant is currently assigned to ATLAS COPCO AIRPOWER, NAAMLOZE VENNOOTSCHAP. The grantee listed for this patent is ATLAS COPCO AIRPOWER, NAAMLOZE VENNOOTSCHAP. Invention is credited to Erik Paul Fabry.
United States Patent |
11,384,758 |
Fabry |
July 12, 2022 |
Cylindrical symmetric volumetric machine with an inlet
ventilator
Abstract
A cylindrical symmetric volumetric machine, includes a housing
(2) with two co-operating rotors (6a, 6b) therein, namely an outer
rotor (6a) mounted rotatably in the housing (2) and an inner rotor
(6b) mounted rotatably in the outer rotor (6a), whereby a
compression chamber (8) is located between the rotors (6a, 6b),
which will move by rotation of the rotors (6a, 6b) from the inlet
side (9a) of the rotors (6a, 6b) to the outlet side (9b) of the
rotors (6a, 6b), wherein the inlet side (9a) of the outer rotor
(6a) is provided with a ventilator (12), to supply air to the
compression chamber (8).
Inventors: |
Fabry; Erik Paul (Wilrijk,
BE) |
Applicant: |
Name |
City |
State |
Country |
Type |
ATLAS COPCO AIRPOWER, NAAMLOZE VENNOOTSCHAP |
Wilrijk |
N/A |
BE |
|
|
Assignee: |
ATLAS COPCO AIRPOWER, NAAMLOZE
VENNOOTSCHAP (Wilrijk, BE)
|
Family
ID: |
1000006428088 |
Appl.
No.: |
16/635,810 |
Filed: |
September 11, 2018 |
PCT
Filed: |
September 11, 2018 |
PCT No.: |
PCT/IB2018/056923 |
371(c)(1),(2),(4) Date: |
January 31, 2020 |
PCT
Pub. No.: |
WO2019/058212 |
PCT
Pub. Date: |
March 28, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20210033090 A1 |
Feb 4, 2021 |
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Foreign Application Priority Data
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|
|
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Sep 21, 2017 [BE] |
|
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2017/5673 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C
2/107 (20130101); F04C 2/1076 (20130101) |
Current International
Class: |
F04C
2/107 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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60147797 |
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Oct 1985 |
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JP |
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477859 |
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Mar 2002 |
|
TW |
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2008/000505 |
|
Jan 2008 |
|
WO |
|
2015/124918 |
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Aug 2015 |
|
WO |
|
Other References
International Search Report for PCT/IB2018/056923 dated Dec. 21,
2018 (PCT/ISA/210). cited by applicant .
Written Opinion of the International Searching Authority for
PCT/IB2018/056923 dated Dec. 21, 2018 (PCT/ISA/237). cited by
applicant.
|
Primary Examiner: Davis; Mary
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
The invention claimed is:
1. A cylindrical symmetric volumetric machine comprising: a housing
(2) with two co-operating rotors (6a, 6b) therein, including an
outer rotor (6a) mounted rotatably in the housing (2) and an inner
rotor (6b) mounted rotatably in the outer rotor (6a); a compression
chamber (8) located between the inner rotor and the outer rotor,
which will move by rotation of the inner rotor and the outer rotor
from the inlet side (9a) of the inner rotor and the outer rotor to
the outlet side (9b) of the inner rotor and the outer rotor; and a
ventilator (12) attached to the outer rotor (6a) at the inlet side
thereof such that the blades rotate upon rotation of the outer
rotor to supply air to the compression chamber (8).
2. The cylindrical symmetric volumetric machine according to claim
1, wherein the outer rotor (6a) is provided with an attachment (13)
on its inlet side (9a) in which the ventilator (12) is built in,
and which is attached to the outer rotor (6a).
3. The cylindrical symmetric volumetric machine according to claim
2, wherein the outer rotor (6a) is mounted rotatably in the housing
(2) by means of a bearing (17) connected to said attachment
(13).
4. The cylindrical symmetric volumetric machine according to claim
1, wherein the ventilator (12) is a radial ventilator (12).
5. The cylindrical symmetric volumetric machine according to claim
4, wherein an additional axial ventilator (12a) is provided in
series with said radial ventilator (12).
6. The cylindrical symmetric volumetric machine according to claim
1, wherein the ventilator (12) is an axial ventilator (12).
7. The cylindrical symmetric volumetric machine according to claim
1, wherein the ventilator (12) is a mixed axial-radial ventilator
(12), whereby the blades (15) have both an axial and radial
section.
8. The cylindrical symmetric volumetric machine according to claim
1, wherein the inner rotor (6b) and the outer rotor (6a) have a
conical shape.
9. The cylindrical symmetric volumetric machine according to claim
1, wherein the machine (1) is provided with an electric motor (20)
with a motor rotor (21) and motor stator (22) to drive the inner
and outer rotor (6a, 6b), whereby the electric motor (20) is
mounted around the outer rotor (6a), whereby the motor stator (22)
directly drives the outer rotor (6a).
10. The cylindrical symmetric volumetric machine according to claim
9, wherein the outer rotor (6a) serves as the motor rotor (21).
11. The cylindrical symmetric volumetric machine according to claim
10, wherein the electric motor (20) is provided with permanent
magnets (23) embedded in the outer rotor (6a).
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a National Stage of International Application
No. PCT/IB2018/056923 filed Sep. 11, 2018, claiming priority based
on Belgium Patent Application No. 2017/5673, filed Sep. 21,
2017.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a cylindrical symmetric volumetric
machine.
Background
A volumetric machine is also known under the name "positive
displacement machine".
In particular, the invention is intended for machines such as
expanders, compressors and pumps with a cylindrical symmetry with
two rotors, namely an inner rotor mounted rotatably in an outer
rotor.
Such machines are already known and are described in U.S. Pat. No.
1,892,217 among others. It is also known that the rotors can have a
cylindrical or conical shape.
It is known that such machines can be driven with an electric
motor.
From Belgian patent application no. BE 2017/5459 it is already
known that the electric motor can be mounted around the outer
rotor, whereby the motor stator directly drives the outer
rotor.
Such machine has many advantages in relation to the known machines
whereby the motor shaft is connected by means of a transmission
with the rotor shaft of the outer or inner rotor.
Thus, the machine will not only be a lot more compact, such that
the footprint is smaller, it also means less shaft seals and
bearings are required.
The efficiency of the machine is largely determined by the fill
ratio of the so-called compression chamber, this is a space between
the lobes of the rotors which will move by rotation of the rotors
from the inlet side to the outlet side and thereby decreases in
volume such that the gas enclosed in the space will be
compressed.
The purpose of the present invention is to improve the fill ratio
of such machine.
SUMMARY OF THE INVENTION
To this end, the invention relates to a cylindrical symmetric
volumetric machine, whereby the machine comprises a housing with
two co-operating rotors therein, namely an outer rotor mounted
rotatably in the housing and an inner rotor mounted rotatably in
the outer rotor, whereby a compression chamber is located between
the rotors, which moves by rotation of the rotors from the inlet
side to the outlet side, characterised in that the inlet side of
the outer rotor is provided with a ventilator, to supply air to the
compression chamber.
This provides the advantage that the ventilator will ensure a
centripetal flow of air at the inlet, such that a better filling of
the compression chamber is obtained.
Therefore, the performance of the machine will increase.
This will also offset any premature compression chamber volume
reduction occurring before it closes.
Another advantage is that the actively sucked in air is also
suitable to cool, for example, a motor which drives the machine,
the outlet or the oil that is used for the lubrication and/or
cooling of components of the machine.
That can be realised by sending the sucked in air along or via said
components before it ends up in the compression chamber.
In a practical embodiment the outer rotor is provided with an
attachment on its inlet side wherein the ventilator is built in,
which is attached to the outer rotor.
This attachment can consist of a hollow cylindrical element, which
is placed with its axis in the extension of the axis of the outer
rotor.
According to a preferred characteristic of the invention the outer
rotor is mounted rotatably in the housing by means of a bearing on
or to said attachment.
The advantage is that a smaller bearing can be used. Indeed, the
attachment can itself be provided with a radially inward oriented
collar, for example, such that the bearing can be attached to or on
this collar.
BRIEF DESCRIPTION OF THE INVENTION
With the intention of better showing the characteristics of the
invention, a few preferred embodiments of a cylindrical symmetric
volumetric machine according to the invention are described
hereinafter by way of an example, without any limiting nature, with
reference to the accompanying drawings, wherein:
FIG. 1 schematically shows a cylindrical symmetric volumetric
machine according to the invention;
FIG. 2 shows a cross-section according to line II-II of FIG. 1;
FIG. 3 schematically shows an alternative embodiment of the section
indicated in FIG. 1 with F3;
FIG. 4 schematically shows a variant of FIG. 3;
FIG. 5 schematically shows another variant of FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
The machine 1 schematically shown in FIG. 1 is a compressor device
in this case.
According to the invention it is also possible that the machine 1
relates to an expander device. The invention can also relate to a
pump device.
The machine 1 is a cylindrical symmetric volumetric machine 1. This
means that the machine 1 has a cylindrical symmetry, i.e. the same
symmetrical properties as a cone.
The machine 1 comprises a housing 2 that is provided with an inlet
opening 3 to suck in gas to be compressed and with an outlet
opening 4 for compressed gas. The housing defines a chamber 5.
Two co-operating rotors 6a, 6b, namely an outer rotor 6a mounted
rotatably in the housing 2 and an inner rotor 6b mounted rotatably
in the outer rotor 6a are located in the chamber 5 in the housing 2
of the machine 1.
Both rotors 6a, 6b are provided with lobes 7 and can turn into each
other co-operatively, whereby between the lobes 7 a compression
chamber 8 is created, the volume of which can be reduced by the
rotation of the rotors 6a, 6b, such that the gas that is caught in
this compression chamber 8 is compressed. The principle is very
similar to the known adjacent co-operating screw rotors.
During the rotation of the rotors 6a, 6b, said compression chamber
8 moves from one end 9a of the rotors 6a, 6b to the other end 9b of
the rotors 6a, 6b.
The end 9a will also be referred to as the inlet side 9a of the
inner and outer rotor 6a, 6b and the end 9b of the inner and outer
rotor 6a, 6b will be referred to as the outlet side 9b in what
follows.
In the example shown, the rotors 6a, 6b have a conical shape,
whereby the diameter D, D' of the rotors 6a, 6b decreases in the
axial direction X-X'. However, this is not necessary for the
invention; the diameter D, D' of the rotors 6a, 6b can also be
constant or vary in another way in the axial direction X-X'.
Such design of rotors 6a, 6b is suitable both for a compressor and
expander device. Alternatively, the rotors 6a, 6b can also have a
cylindrical form with a constant diameter D, D'. They can then
either have a variable pitch, such that there is a built-in volume
ratio, in the case of a compressor or expander device, or a
constant pitch, in the case the machine 1 relates to a pump
device.
The axis 10 of the outer rotor 6a and the axis 11 of the inner
rotor 6b are fixed axes 10, 11, this means that the axes 10, 11
will not move in relation to the housing 2 of the machine 1,
however they do not run parallel, but are located at an angle
.alpha. in relation to each other, whereby the axes intersect in
point P.
However, this is not necessary for the invention. For example, if
the rotors 6a, 6b have a constant diameter D, D', the axes 10, 11
can nevertheless run parallel.
According to the invention the inlet side 9a of the outer rotor 6a
is provided with a ventilator 12, to supply air to the compression
chamber 8.
This means that the ventilator 12 will turn with the outer rotor
6a, such that when the rotors 6a, 6b turn, the ventilator 12 will
also start running.
In this case the ventilator 12 is a radial ventilator 12.
In the example shown in FIGS. 1 and 2, the outer rotor 6a is
provided with an attachment 13 on the inlet side 9a in which the
ventilator 12 is built in, which is attached to the outer rotor
6a.
In this case, the attachment 13 comprises a hollow cylindrical
form, which is placed with its axis in the extension of the axis 10
of the outer rotor 6a.
The attachment 13 has a wall 14 with a certain thickness A, whereby
ventilator blades 15 have been mounted in this wall 14.
It is not excluded that the height of one or more of the blades 15
decreases axially from the inside to the outside in the radial
direction.
In this way the reduced contour can be accommodated.
The rotors 6a, 6b are mounted on bearings in the machine 1, whereby
the inner rotor 6b on one end 9a is mounted in the machine 1 on a
bearing 16 and the other end 9b of the inner rotor 6b is supported
or borne by the outer rotor 6a as it were.
In the example shown, the outer rotor 6a is mounted at both ends
9a, 9b in the machine 1 with bearings 17, 18.
As shown in FIG. 1, the outer rotor at the inlet side 9a is mounted
rotatably in the housing 2 by means of a bearing 17 on or to said
attachment 13.
The attachment 13 is provided with a radially inward oriented
collar 19, on which said bearing 17 is mounted.
Consequently this bearing 17 can be made much smaller, i.e. with a
smaller diameter, compared to the case whereby the bearing 17 is
mounted directly on the outer rotor 6a itself.
Further, the machine 1 is also provided with an electric motor 20
which will drive the rotors 6a, 6b. This motor 20 is provided with
a motor rotor 21 and a motor stator 22.
In this case, but not necessarily, the electric motor 20 is mounted
around the outer rotor 6a whereby the motor stator 22 directly
drives the outer rotor 6a.
In the example shown, this is realised because the outer rotor 6a
also serves as motor rotor 21.
The electric motor 20 is provided with permanent magnets 23 which
are embedded in the outer rotor 6a.
It is also possible of course that these magnets 23 are not
embedded in the outer rotor 6a, but are mounted on the outside
thereof for example.
Instead of an electric motor 20 with permanent magnets 23 (i.e. a
synchronous permanent magnet motor), an asynchronous induction
motor can also be applied, whereby the magnets are replaced with a
squirrel-cage rotor.
Induction from the motor stator generates a current in the
squirrel-cage rotor.
On the other hand, the motor 20 can also be a reluctance type or
induction type or a combination of types.
The motor stator 22 is mounted around the outer rotor 6a in a
covering way, whereby in this case it is located in the housing 2
of the machine 1.
In this way the lubrication of the motor 20 and the rotors 6a, 6b
can be controlled together, as they are located in the same housing
2 and consequently are not closed off from each other.
The operation of the device 1 is very simple and as follows.
During the operation of the machine 1, the motor stator 22 will
drive the motor rotor 21 and therefore drive the outer rotor 6a in
the known way.
The outer rotor 6a will help drive the inner rotor 6b, and by the
rotation of the outer rotor 6a, the ventilator 12 will also
turn.
Due to the operation of the ventilator 12 gas will be sucked in via
the inlet opening 3. This gas will end up in the compression
chamber 8 between the rotors 6a, 6b.
Because the ventilator 12 will ensure an active supply or flow of
gas, the fill ratio of the compression chamber 8 will be
increased.
Furthermore, the gas, when the gas is sucked in via the inlet
opening 3, will flow past the motor rotor 21 and the motor stator
22. In this way the gas will be able to ensure an active cooling of
the motor 20.
Due to the rotation this compression chamber 8 moves to the outlet
4 and at the same time will reduce in terms of volume to thus
realise a compression of the gas.
The compressed gas can then exit the machine 1 via the outlet
opening 4.
It is not excluded that during the compression, liquid is injected
in the machine 1.
Said liquid can both be water and a synthetic or non-synthetic
oil.
FIG. 3 shows an alternative embodiment of the ventilator 12,
whereby it is now an axial ventilator 12.
In this case the attachment 13 is not cylindrical, but more
conical. This, however, is not necessary. The axial ventilator 12
is built into the radially inward oriented collar 19.
In FIG. 4 the radial ventilator 12 of FIG. 1 is shown in
combination with an additional axial ventilator 12a which are
placed in series with each other.
In this case the additional axial ventilator 12a is placed in front
of the radial ventilator 12, seen in the flow direction of the
sucked in air. It is also possible of course that the radial
ventilator 12 is placed in front of the additional axial ventilator
12a.
The additional axial ventilator 12a is mounted around the
attachment 13.
FIG. 5 shows an additional variant whereby in this case the
ventilator 12 is a mixed axial-radial ventilator 12, whereby the
blades 15 have both an axial and a radial section.
The operation of the ventilator 12 in the embodiments of FIGS. 3 to
5 is analogue to the operation of the embodiment in FIGS. 1 and
2.
The present invention is by no means limited to the embodiments
described as an example and shown in the drawings, but a
cylindrical symmetric volumetric machine according to the invention
can be realised in all kinds of forms and dimensions, without
departing from the scope of the invention.
* * * * *